Knockdown from carbofuran, bioneopynamin and decamethrin poisoning will be studied by measuring the site of failure of the optic ganglion to jumping muscle nervous pathway in house fly. Disruption in the reflex start-to-fly response will be localized at the single cell level by intracellular recording the dye-injection of specific neurons in the thoracic ganglion. This work will be supported by a general study of the neuroanatomy of the thoracic ganglion of house fly to locate motor units involved in reflex response pathways. The purpose is to define insecticide poisoning in terms of specific actions on central nervous elements. The actions of pyrethroid insecticides on insect motor nerve terminals will be studied to evaluate the nerve terminal as a primary lesion site in establishing a structure-activity relationship in pyrethroids.